The best time to visit is June through October, when the mountain roads are clear of snow and the wilderness is accessible. July and August are warm (daytime highs in the mid-80s Fahrenheit) but rarely oppressive at this elevation. Autumn brings excellent colour in the aspen groves and fewer visitors.
Spring (April-May) can be rewarding for wildflowers and high river flows, but snow remains on upper trails and some forest roads may still be closed. Check conditions before planning backcountry trips.
Winter brings heavy snowfall — Quincy is a real mountain town, not a ski resort, and the infrastructure assumes locals who know how to deal with snow. The skiing at nearby Plumas Eureka State Park is very modest.